1. Field of the Invention
The present invention relates to cap/container interface or vapor pressure indicators for fuel tanks, with sensors located in the cap for the fuel tank, in an opening of the fuel tank that the cap fits over, or in another part of the fuel tank.
2. Description of the Prior Art
Millions of gallons of fuel are lost each year due to ill-fitting fuel caps. Losses may be caused by evaporation, expansion of the fuel as the fuel tank heats up when a vehicle is in operation, splashing, etc. The vehicle's fuel pump may loose efficiency when the fuel cap is loose. Fuel may not feed properly and efficiently into injectors or carburetors. Loose fitting fuel caps may it more difficult for fuel feeding systems to get fuel to the combustion chambers with a proper air and fuel mixture. As a result, motors become less efficient, and deliver less energy for the fuel used. Motors generate excessive heat, due to inefficient or incomplete combustion. Motors running on an inefficient fuel mixture have more friction because of increased heat and increased particulate matter resulting from incomplete combustion. All of these factors result in decreased mileage, and in increased emissions and air pollutants. There have been previous inventions for detecting when a tank has a leak or is empty, but none that are equivalent to the present invention.
U.S. Pat. No. 5,105,663, issued on Apr. 21, 1992, to Ernst Kuhlen, discloses an apparatus and method for measuring low fuel level in a fuel tank, rather than low cap/container interface or vapor pressure, as in the instant invention.
U.S. Pat. No. 5,146,783, issued on Sep. 15, 1992, to Walter Jansche, Erich Zabler and Anton Dukart, discloses a liquid container hydrostatic level gauge, which uses a differential pressure sensor to determine how much fuel is left, rather then low cap/container interface or vapor pressure as in the instant invention.
U.S. Pat. No. 5,886,266, issued on Mar. 23, 1999, to Rudolf Stiller, Andreas Maennchen and Norbert Schmidt, discloses a pressure sensor that is inserted into a fuel tank, to detect low pressure that indicates a leak in the tank. The instant invention is distinguishable, in that it sends a warning signal to an outside device, such as a receiver on a key ring.
U.S. Pat. No. 6,571,778, issued on Jun. 3, 2003, to Thomas Herm and Frank Kutzner, discloses a method for testing the leak-tightness of a vehicle's fuel tank, by detecting the tank's internal pressure, and making adjustments for changes in the vehicle's speed.
U.S. Pat. No. 6,822,565, issued on Nov. 23, 2004, to Keith A. Thomas, Timothy A. Kearns and Bruce R. Davis, discloses a wireless gauge alert that sends a signal to a receiver, causing a user notification signal to be generated, when certain conditions within a liquid fuel or pressure tank are present, such as the tank being near empty, or pressure in the tank being low. However, it does not disclosure the placement of a pressure sensor in a motor vehicle fuel cap or tank opening, or a blinking light on a key chain attachment as a user notification signal, as in the instant invention.
U.S. Pat. No. 7,051,718, issued on May 30, 2006, to Masafumi Tsuruta, discloses a fuel vapor leak check module, with housing that is close to a canister by inserting a canister port into the canister.
U.S. Pat. No. 7,140,235, issued on Nov. 28, 2006, to Kurt D. Mc Lain and Michael J. Pitsch, discloses a leak detection system for a vehicle fuel tank, including a sensor that generates a pressure signal.
U.S. Pat. No. 7,221,363, issued on May 22, 2007, to John K. Roberts et al., discloses a rear view mirror assembly, causing various information about a vehicle's status to be displayed in its rear view mirror.
U.S. Patent Application Publication No. 2004/0215407, published on Oct. 28, 2004, to Jeffrey L. Thielman and Rhonda L. Wilson, discloses an apparatus and method for integrating a fuel supply and a fuel level sensing pressure sensor.
German Patent No. 20301168, published on Apr. 17, 2003, to PROPAN RHEINGAS GMBH & CO. KG., discloses a monitoring system for fluid gas tanks having a pressure and content sensor and a wireless connection to a central office. (Unfortunately, only the English abstract and the drawing were available at the U.S. Patent & Trademark Office.)
South Korean Patent No. 200308957, published on Nov. 22, 2003, inventor S. Y. Lee, discloses an apparatus and method for alerting the driver of low pressure in the fuel tank. (Unfortunately, only the English abstract and the drawing were available at the U.S. Patent & Trademark Office.)
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention.